Briefly tell the story written in Chapter 15 about a young man and his mother.

It's an old Eskimo tale of a young man who brings home a beautiful bride. His mother is jealous of the bride, because the mother wants the son to herself. The mother offers to braid her daughter-in-law's hair and while she does so, she strangles the girl, then peels the dead woman's face skin and places it on her own face as a mask. When the son returns, he lies with his mother, but his wet clothes shrink the mask to reveal it is his mother. The son recoils in horror and runs away, never to return.